A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions

Conservation agriculture involves reduced tillage, permanent soil cover and crop rotations to enhance soil fertility and to supply food from a dwindling land resource. Recently, conservation agriculture has been promoted in Southern Africa, mainly for maize-based farming systems. However, maize yields under rain-fed conditions are often variable. There is therefore a need to identify factors that influence crop yield under conservation agriculture and rain-fed conditions. Here, we studied maize grain yield data from experiments lasting 5 years and more under rain-fed conditions. We assessed the effect of long-term tillage and residue retention on maize grain yield under contrasting soil textures, nitrogen input and climate. Yield variability was measured by stability analysis. Our results show an increase in maize yield over time with conservation agriculture practices that include rotation and high input use in low rainfall areas. But we observed no difference in system stability under those conditions. We observed a strong relationship between maize grain yield and annual rainfall. Our meta-analysis gave the following findings: (1) 92% of the data show that mulch cover in high rainfall areas leads to lower yields due to waterlogging; (2) 85% of data show that soil texture is important in the temporal development of conservation agriculture effects, improved yields are likely on well-drained soils; (3) 73% of the data show that conservation agriculture practices require high inputs especially N for improved yield; (4) 63% of data show that increased yields are obtained with rotation but calculations often do not include the variations in rainfall within and between seasons; (5) 56% of the data show that reduced tillage with no mulch cover leads to lower yields in semi-arid areas; and (6) when adequate fertiliser is available, rainfall is the most important determinant of yield in southern Africa. It is clear from our results that conservation agriculture needs to be targeted and adapted to specific biophysical conditions for improved impact

Cytokine Levels Correlate with Immune Cell Infiltration after Anti-VEGF Therapy in Preclinical Mouse Models of Breast Cancer

The effect of blocking VEGF activity in solid tumors extends beyond inhibition of angiogenesis. However, no studies have compared the effectiveness of mechanistically different anti-VEGF inhibitors with respect to changes in tumor growth and alterations in the tumor microenvironment. In this study we use three distinct breast cancer models, a MDA-MB-231 xenograft model, a 4T1 syngenic model, and a transgenic model using MMTV-PyMT mice, to explore the effects of various anti-VEGF therapies on tumor vasculature, immune cell infiltration, and cytokine levels. Tumor vasculature and immune cell infiltration were evaluated using immunohistochemistry. Cytokine levels were evaluated using ELISA and electrochemiluminescence. We found that blocking the activation of VEGF receptor resulted in changes in intra-tumoral cytokine levels, specifically IL-1β, IL-6 and CXCL1. Modulation of the level these cytokines is important for controlling immune cell infiltration and ultimately tumor growth. Furthermore, we demonstrate that selective inhibition of VEGF binding to VEGFR2 with r84 is more effective at controlling tumor growth and inhibiting the infiltration of suppressive immune cells (MDSC, Treg, macrophages) while increasing the mature dendritic cell fraction than other anti-VEGF strategies. In addition, we found that changes in serum IL-1β and IL-6 levels correlated with response to therapy, identifying two possible biomarkers for assessing the effectiveness of anti-VEGF therapy in breast cancer patients

Nodal-Dependent Mesendoderm Specification Requires the Combinatorial Activities of FoxH1 and Eomesodermin

Vertebrate mesendoderm specification requires the Nodal signaling pathway and its transcriptional effector FoxH1. However, loss of FoxH1 in several species does not reliably cause the full range of loss-of-Nodal phenotypes, indicating that Nodal signals through additional transcription factors during early development. We investigated the FoxH1-dependent and -independent roles of Nodal signaling during mesendoderm patterning using a novel recessive zebrafish FoxH1 mutation called midway, which produces a C-terminally truncated FoxH1 protein lacking the Smad-interaction domain but retaining DNA–binding capability. Using a combination of gel shift assays, Nodal overexpression experiments, and genetic epistasis analyses, we demonstrate that midway more accurately represents a complete loss of FoxH1-dependent Nodal signaling than the existing zebrafish FoxH1 mutant schmalspur. Maternal-zygotic midway mutants lack notochords, in agreement with FoxH1 loss in other organisms, but retain near wild-type expression of markers of endoderm and various nonaxial mesoderm fates, including paraxial and intermediate mesoderm and blood precursors. We found that the activity of the T-box transcription factor Eomesodermin accounts for specification of these tissues in midway embryos. Inhibition of Eomesodermin in midway mutants severely reduces the specification of these tissues and effectively phenocopies the defects seen upon complete loss of Nodal signaling. Our results indicate that the specific combinations of transcription factors available for signal transduction play critical and separable roles in determining Nodal pathway output during mesendoderm patterning. Our findings also offer novel insights into the co-evolution of the Nodal signaling pathway, the notochord specification program, and the chordate branch of the deuterostome family of animals

Minhas experienciações no espaço tempo da sala de aula: é possível integrar os saberes? Em que condições?

In this survey, done from teaching experience, I intend to discuss about reflexive education as an agent for transformation of daily practice, by finding in higher education, the difficulty of generating new forms of relations, especially regarding the practice of activities in classroom. The research was developed in two stages: first, in relation to my activities with the Postgraduate Program in the Faculdade de Educação and second, in a class composed of 40 students registered in the Atividade de Integração Curricular, the first year of the bachelor of Sistemas de Informação, during the year 2010. Based on the uncertainty of the way to go, the survey search evidences of engaging of the students with the educational relationship. Offer moments of reflection about the dynamics of education with the aim to discuss the production of subjectivities in classroom activities. Within the qualitative perspective, as a matter of field, I used the methodology of researchaction. This technique aims to identify strategies of planned action which are implemented, and then systematically submitted to observation, questioning and transformation. Together, I chose to use the cartography method, which is presented as a way to promote access to that which stimulates thinking, thus tracking what is not relevant to a systemic representation. While this process of reflection and significant buildings asked for students to answer a questionnaire and prepare reports. When I connected the data points have emerged producing voice to thoughts, doubts, fears and expectations of students. I understood how necessary it is to learn to learn, especially in times of uncertainty. Even viewing that the educational system, largely is based on principles of instrumental rationality associated with students experiences in teaching conservative and traditional I see that they have a called to introduce a other order, especially in terms dialogical relations and collective.Neste estudo, realizado a partir de experiências pedagógicas, intenciono problematizar a educação reflexiva como agente de transformação da prática diária, a partir da constatação, na educação superior, da dificuldade de engendrar novas formas de relações, de modo especial no que tange à prática das atividades no espaço tempo da sala de aula. A pesquisa foi elaborada em dois momentos: o primeiro, em relação às minhas atividades junto ao Programa de Pós-Graduação na Faculdade de Educação e, o segundo, em uma turma composta por 40 estudantes matriculados na Atividade de Integração Curricular, do primeiro ano do curso de bacharelado em Sistemas de Informação, durante o ano de 2010. A proposta de estudo, embasada na incerteza do caminho a ser trilhado, busca evidências do engajamento dos estudantes frente à relação educacional. Oportunizei momentos de reflexão acerca da dinâmica educacional, no intuito de problematizar as atividades em sala de aula. Dentro da perspectiva qualitativa, como procedimento de campo, utilizei a metodologia de pesquisa–ação. Nesta procurei mapear estratégias de ação planejada as quais são implementadas e, a seguir, sistematicamente submetidas à observação, problematização e transformação. Conjuntamente, optei por utilizar o método cartográfico, o qual se apresentou como um caminho para promover o acesso àquilo que estimula o pensar, possibilitando o acompanhamento ao que foge a uma representação sistêmica. Em meio a esse processo de significativas reflexões e construções solicitei aos estudantes responderem um questionário e elaborarem relatos. Ao relacionar os dados, emergiram aspectos produzindo voz a pensamentos, dúvidas, medos e expectativas dos estudantes. Compreendi o quão necessário é aprender a aprender, de modo especial, em tempos de incertezas. Mesmo verificando que o sistema educacional, em grande parte, é baseado em princípios de racionalidade instrumental associados às experiências dos estudantes em atividades de ensino conservador e tradicional, percebo que estes apresentam um apelo à introdução de outra ordem, principalmente, no que tange às relações dialógicas e coletivas